Hypertrophic cardiomyopathy is a not uncommon form of heart disease, of unknown origin. We are seeking to establish a cell line derived from heart tissue removed from patients with hypertrophic cardiomyopathy at the time of surgery to help determine the cellular cause of this disease. A. Sterile tissue is obtained from the operating room after left ventricular myotomy and myomectomy. The tissue is manually dispersed and incubated at 37 degrees Celsius, 10% C02, in enriched medium. When a cell layer has grown up, the cells are passaged into flasks, and the culture medium adjusted as needed. The cells seem to grow very slowly, with doubling times of several weeks. They also have unusual morphology and it is nor clear at this time if they are fibroblast or smooth muscle in origin. B. Once the cell line is established and further characterized, we will study its response to growth factors such as fibroblast growth factor and platelet-derived growth factor. We will also examine the intrinsic production of these growth factors by the cardiac cells. The etiology of hypertrophic cardiomyopathy remains obscure. On a basic level, understanding the function of the individual cellular components may lead to a clearer understanding of the disease as a whole. This work should ultimately complement clinical work being done in the same area.